Differentially zoned inking means



Sept. 20, 1960 c. B. LYON 2,952,862

' DIFFERENTIALLY zomazn INKING MEANS Filed Nov. 2:5, 195s INVENTOR.

CLIFFORD B. LYON ATTORNEYS United States Patent .0

DIFFERENTIALLY ZONED INKING MEANS Clifford B. Lyon, Sandusky, Ohio, assignor to Fingerprint Identification Service Co., Sandusky, Ohio, 2 corporation of Ohio Filed Nov. 23, 1956, Ser. No. 624,019

3 Claims. (Cl. 15-209) This invention relates to inking devices for rubber stamps and the like.

An object of the invention is to provide an ink transfer device where high-capacity ink storage is achieved through the provision of a porous body having gross voids therein to constitute a high-capacity ink reservoir zone.

Another object of the invention is to provide an inking device in which the supply of ink from the reservoir zone to the ink transfer surface of the device is accomplished through a boundary zone of porous material which is free of gross voids, the boundary zone being contiguous to the reservoir zone.

Another object of the invention is to provide an inking device wherein the high-capacity storage and the distribution of the ink is accomplished through contiguous reservoir and boundary zones, the boundary zone being encased in a fabric which serves to improve the ink transfer function of the device.

These and other objects and advantages of the invention will become more fully apparent from a complete reading of the specification and from the drawings in which:

Figure 1 is a schematic elevational view of a device embodying the invention.

Figure 2 is a view illustrating one of the many possible ways in which the device shown in Figure 1 might be mounted.

Figure 3 is a schematic elevational view of another device embodying the invention.

Figures 4 and 5 are views illustrating two of many possible ways in which the device shown in Figure 3 might be mounted.

The pad generally indicated by the reference numeral in Figures 1 and 2 comprises a permeable calcium sulfate slab 11. The slab is permeated with an ink 12 in such a manner that the ink is distributed throughout the body of the slab. The slab 11 has extremely small inkabsorbing interstices and comprises an inner or lower reservoir zone 13 which includes relatively gross voids and a boundary zone 14 which is free of gross voids. A fabric 16 is preferably provided on the outer surface of the boundary zone 14.

It is presently preferred that the slab 11 be fabricated by separately forming and filling with ink the reservoir zone .13 and the boundary zone 14 and then subsequently pressing or positioning these two slabs together and causing them to be retained together by frictional contact or by encasing them in a suitable housing or the like.

To make the boundary zone 14, water is added to dehydrated calcium sulfate (plaster of Paris) and the mix is poured into the mold and allowed to dry for 24 hours to form a large, fine pored, permeable plate. Pore size may be increased or decreased by increasing or decreasing the ratio of water in the mix. The dry plate is cut to size and then individual slabs are suspended in a bath of ink so that the ink may permeate the slab from both sides. A

slab Ms" thick should require about 48 hours to become totally saturated with ink, the degree of saturation being determinable by weighing. If the required time for total saturation varies widely from 48 hours, departure from standard pore size is indicated. In such case, the water ratio in subsequent mixes is varied until a proper pore size is indicated by an elapsed time for total saturation of approximately 48 hours.

The above directions apply to the making of the boundary zone where the ink viscosity is comparable to the inks given by way of example in U.S. Patent 2,723,476. The values given may, if desired, be approximately varied where higher or lower ink viscosities obtain.

The reservoir zone may be made by adding Water to dehydrated calcium sulfate and pouring the mix into a suitable mold, the water in this case containing a suitable blowing agent, such as sodium bicarbonate. The water to dehydrated calcium sulfate ratio may be the same as that in the manufacture of the boundary zone. The ratio of the blowing agent, such as sodium bicarbonate to the dehydrated calcium sulfate is preferably about 1.0% by weight, although this ratio may be varied between a relatively low figure at which there is a significant, but not substantial, blowing effect (approximately .05%) to a figure short of where significant disintegration occurs (approximately 5.0%). The freshly poured mix within the mold is subjected to the action of the blowing agent as it dries to form a permeable plate in which there are included numerous relatively gross voids. The dried plate is cut to size and the individual slabs are suspended in a bath of ink so that the ink may permeate the slabs from both sides.

Alternatively, the mix which forms the reservoir zone may be blown by whipping.

The fully saturated boundary zone slabs and reservoir zone slabs are joined together as mentioned above. Either before, during or after such joining operation the boundary zone 14 may be covered with the fabric 16. The fabric 16 is preferably a woven fabric of relatively close weave or an unwoven fabric of equivalent characteristics. The fabric should be essentially comprised of a nonmonofilamentous yarn, such as cotton, Wool, or other natural fiber, or non-monofilamentous forms of the various organic resinous materials which are suitable for use as yarns and which exhibit capillary action to a significant degree when wetted with liquid. In general, I find it preferable to employ a liquid petrolatum base or other mineral oil base aniline dye ink of relatively high velocity. The inks specified in U.S. Patent No. 2,723,476 may be employed if desired, although for the applications to which the present invention is directed it may be preferred to employ inks of somewhat lower velocities and/ or viscosities.

Carbon black inks should be avoided because the permeable calcium sulfate slab will precipitate out the carbon, and the liquid withdrawn from the pad will have a weak color unsuitable for the intended purpose of the device.

A suitable case such as that illustrated in Figure 2 may be provided to house the bad 10. To minimize the possibility of damage to the pad, the base 18 of the case may be constructed to snugly fit the pad and to closely conform to the bottom surface of the pad in order to obtain uniform support. The interior dimensions of the lid 19 may also be as closely dimensioned as practical to the upper portion of the pad, with o'nly a small spacing or no spacing between the lid 19 and the pad 10 in the closed position.

The fabric 16 may be cast in the boundary zone 14 or may be impressed in the material making up such zone before setting thereof, or it may be positioned on the boundary Zone at a later time and suitably anchored thereo'n;

' Shown in Figure 2 is a roll generally indicated by the reference numeral 20. The roll comprises a cylinder 21 or permeable calcium sulfate which is permeated with 22. The eylinder 21 includes an inner reservoir zone 2,3 in which are formed relatively gross voids and outer boundary zone 24 in which there are substan tially no gross voids.

The cylinder 21 may be covered with a fabric 26. I The specifications for such fabric may be the same as those for the fabric 16. Similarly to the fabric 16, the fabric 26 may be cast with the boundary zone 24 or may be impressed thereeii prior to softening thereof or maybe anchored therea'round at a later stage.

Inlthe manufacture of the cylinder 21 it is preferred that the reservoir zene 23 and the boundary zone 24 be separately formed and saturated with ink prior to being ofnbined as by sliding the reservoir zone 23 into the initial hollow-shell form of the boundary zone 24. The

reservoir zone 23 and the boundary zone 24 may be cast in suitable cylindrical molds with a suitable core being provided in the case of the boundary zone, A hollow shaft 28 may be molded in the center of the reservoir Zone during casting thereof. 7

In the manufacture of the reservoir zone 23 and the boundary zone 24, the same specifications inay be followed as are disclosed above in connection with the manufacture of the reservoir zone 13 and the boundary zone 14.

A suitable stand such as that illustrated in Figure 4 may be provided to mount the roll 20. A pair of spring arms 4 the further provision of an encasing or facing fabric to provide a resilient inking surface and to draw the ink out exteriorly from the solid porous body which contains and distributes the ink. a

From the above description, it will be apparent that many modifications in the disclosed examples of my invention will suggest themselves; The scope of the invention is defined by the following claims.

What is claimed is: a

1. An inking device comprising a porous body of permeable calcium sulfate dehydrate, said'bodyi having a reservoir zone with a plurality of relatively gross voids formed therein and also having a boundary zone contiguous with said reservoir zone and having only relatively small voids, a mineral oil base ink in said voids and interstitially dispersed throughout said body, both the relatively gross and relatively small voids being of such size that capillary action of the ink within the zones takes place, and a fabric associated with said body and secured to the outer surface of said boundary zone. v 2. An inking pad comprising a porous slab of penile able calcium sulfate dehydrate, said slab having a reservoir zone with a plurality of relatively gross voids formed therein and also having a boundary zone contiguous with 30 may be fixed to a base 31 and may be releasably reeived in the ends of the hollow shaft 28. 7

Another stand is illustrated in Figure 5. Here the hollow shaft 28 is received on a rod 33 which is fixed to a base 34. The roll 20 is held in spaced relation from the base by ears 35 formed in the rod 33. In the several uses of the invention illustrated in Figures 2, 4, and Sand in other similar uses, the invention provides an inking device in which the supply of ink from the reservoir zone to tlie ink transfer surface is accomplished through a boundary zone of porous material whieh is free of gross voids while, at the same time, the device as a whole exhibits a great ink capacity and has an eiitreinely long service life which far exceeds those of present stamp pads;

The invention may be regarded as involving the achievement of a high-capacity inking' 'devie through the employment together of a zone of relatively gross voids and a permeable bounding zone which is free of gross voids in order to accomplish even ink distribution and said reservoir zone and having only relatively small voids, -a mineral oil ink in said voids and interstitia'ily dispersed throughout said slab, both the relatively gross relatively small voids being of such size that capillary action of the ink within the zones takes place, and a fabric assoeiated with said slab and secured to the outer surfaee of said boundary zone.

3. An inking roll comprising a porous cylinder of permeable calcium sulfate dehydrate, said cylinder having a reservoir zone with a plurality of relatively gross voids formed therein and also having a boundary zone contiguous with said reservoir acne and having only rela tively small voids, a mineral oil base in said voids and interstitially dispersed throughout said cylinder, both the relatively gross and relatively smallvoids being of si leh size that capillary-action of the ink the zones takes place, an axially extending shaft in said cylindenand a fabric associated with said cylinder and secured to the outer surface of said boundary zone.

References Cited in the file of this patent UNITED STATES PATENTS 538,837 Laughton May 7, 1 895 p 603,841 Fairbank et a1. May 10; 1898 1,363,017 Russo Dec. 21, 1920 2,392,521 Chollar 1311. 8, 1946 2,723,476 Lyon NOV. 15, 1955 

